1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Real Time Clock interface for Linux on the BVME6000 4 * 5 * Based on the PC driver by Paul Gortmaker. 6 */ 7 8 #define RTC_VERSION "1.00" 9 10 #include <linux/types.h> 11 #include <linux/errno.h> 12 #include <linux/miscdevice.h> 13 #include <linux/ioport.h> 14 #include <linux/capability.h> 15 #include <linux/fcntl.h> 16 #include <linux/init.h> 17 #include <linux/poll.h> 18 #include <linux/module.h> 19 #include <linux/rtc.h> /* For struct rtc_time and ioctls, etc */ 20 #include <linux/bcd.h> 21 #include <asm/bvme6000hw.h> 22 23 #include <asm/io.h> 24 #include <linux/uaccess.h> 25 #include <asm/setup.h> 26 27 /* 28 * We sponge a minor off of the misc major. No need slurping 29 * up another valuable major dev number for this. If you add 30 * an ioctl, make sure you don't conflict with SPARC's RTC 31 * ioctls. 32 */ 33 34 static unsigned char days_in_mo[] = 35 {0, 31, 28, 31, 30, 31, 30, 31, 31, 30, 31, 30, 31}; 36 37 static atomic_t rtc_status = ATOMIC_INIT(1); 38 39 static long rtc_ioctl(struct file *file, unsigned int cmd, unsigned long arg) 40 { 41 volatile RtcPtr_t rtc = (RtcPtr_t)BVME_RTC_BASE; 42 unsigned char msr; 43 unsigned long flags; 44 struct rtc_time wtime; 45 void __user *argp = (void __user *)arg; 46 47 switch (cmd) { 48 case RTC_RD_TIME: /* Read the time/date from RTC */ 49 { 50 local_irq_save(flags); 51 /* Ensure clock and real-time-mode-register are accessible */ 52 msr = rtc->msr & 0xc0; 53 rtc->msr = 0x40; 54 memset(&wtime, 0, sizeof(struct rtc_time)); 55 do { 56 wtime.tm_sec = bcd2bin(rtc->bcd_sec); 57 wtime.tm_min = bcd2bin(rtc->bcd_min); 58 wtime.tm_hour = bcd2bin(rtc->bcd_hr); 59 wtime.tm_mday = bcd2bin(rtc->bcd_dom); 60 wtime.tm_mon = bcd2bin(rtc->bcd_mth)-1; 61 wtime.tm_year = bcd2bin(rtc->bcd_year); 62 if (wtime.tm_year < 70) 63 wtime.tm_year += 100; 64 wtime.tm_wday = bcd2bin(rtc->bcd_dow)-1; 65 } while (wtime.tm_sec != bcd2bin(rtc->bcd_sec)); 66 rtc->msr = msr; 67 local_irq_restore(flags); 68 return copy_to_user(argp, &wtime, sizeof wtime) ? 69 -EFAULT : 0; 70 } 71 case RTC_SET_TIME: /* Set the RTC */ 72 { 73 struct rtc_time rtc_tm; 74 unsigned char mon, day, hrs, min, sec, leap_yr; 75 unsigned int yrs; 76 77 if (!capable(CAP_SYS_ADMIN)) 78 return -EACCES; 79 80 if (copy_from_user(&rtc_tm, argp, sizeof(struct rtc_time))) 81 return -EFAULT; 82 83 yrs = rtc_tm.tm_year; 84 if (yrs < 1900) 85 yrs += 1900; 86 mon = rtc_tm.tm_mon + 1; /* tm_mon starts at zero */ 87 day = rtc_tm.tm_mday; 88 hrs = rtc_tm.tm_hour; 89 min = rtc_tm.tm_min; 90 sec = rtc_tm.tm_sec; 91 92 leap_yr = ((!(yrs % 4) && (yrs % 100)) || !(yrs % 400)); 93 94 if ((mon > 12) || (mon < 1) || (day == 0)) 95 return -EINVAL; 96 97 if (day > (days_in_mo[mon] + ((mon == 2) && leap_yr))) 98 return -EINVAL; 99 100 if ((hrs >= 24) || (min >= 60) || (sec >= 60)) 101 return -EINVAL; 102 103 if (yrs >= 2070) 104 return -EINVAL; 105 106 local_irq_save(flags); 107 /* Ensure clock and real-time-mode-register are accessible */ 108 msr = rtc->msr & 0xc0; 109 rtc->msr = 0x40; 110 111 rtc->t0cr_rtmr = yrs%4; 112 rtc->bcd_tenms = 0; 113 rtc->bcd_sec = bin2bcd(sec); 114 rtc->bcd_min = bin2bcd(min); 115 rtc->bcd_hr = bin2bcd(hrs); 116 rtc->bcd_dom = bin2bcd(day); 117 rtc->bcd_mth = bin2bcd(mon); 118 rtc->bcd_year = bin2bcd(yrs%100); 119 if (rtc_tm.tm_wday >= 0) 120 rtc->bcd_dow = bin2bcd(rtc_tm.tm_wday+1); 121 rtc->t0cr_rtmr = yrs%4 | 0x08; 122 123 rtc->msr = msr; 124 local_irq_restore(flags); 125 return 0; 126 } 127 default: 128 return -EINVAL; 129 } 130 } 131 132 /* 133 * We enforce only one user at a time here with the open/close. 134 */ 135 static int rtc_open(struct inode *inode, struct file *file) 136 { 137 if (!atomic_dec_and_test(&rtc_status)) { 138 atomic_inc(&rtc_status); 139 return -EBUSY; 140 } 141 return 0; 142 } 143 144 static int rtc_release(struct inode *inode, struct file *file) 145 { 146 atomic_inc(&rtc_status); 147 return 0; 148 } 149 150 /* 151 * The various file operations we support. 152 */ 153 154 static const struct file_operations rtc_fops = { 155 .unlocked_ioctl = rtc_ioctl, 156 .open = rtc_open, 157 .release = rtc_release, 158 .llseek = noop_llseek, 159 }; 160 161 static struct miscdevice rtc_dev = { 162 .minor = RTC_MINOR, 163 .name = "rtc", 164 .fops = &rtc_fops 165 }; 166 167 static int __init rtc_DP8570A_init(void) 168 { 169 if (!MACH_IS_BVME6000) 170 return -ENODEV; 171 172 pr_info("DP8570A Real Time Clock Driver v%s\n", RTC_VERSION); 173 return misc_register(&rtc_dev); 174 } 175 module_init(rtc_DP8570A_init); 176